1. Field of the Invention
The present invention relates to a mobile communication terminal, and more particularly, to a mobile communication terminal and a controlling method thereof. Although the present invention is suitable for a wide scope of applications, it is particularly suitable for enhancing wireless communication performance in a manner of reducing influence of electric waves through grounding.
2. Discussion of the Related Art
Generally, a mobile communication terminal is conveniently carried by a user and enables the user to exchange various kinds of information of video, audio, character, and the like with a correspondent user via wireless communication or enables the user to be provided with various services by accessing a prescribed server. As an example of the mobile communication terminal, there is a mobile phone, a PDA (personal digital assistant), or the like.
The mobile communication terminal and more particularly, the mobile phone has evolved from an early bar type into a flip type, a folder type, and a slide type in sequence.
The mobile communication terminal conducts wireless communication for making a phone call or performing data communication. The mobile communication terminal eventually generates considerable electromagnetic waves from various electronic parts mounted on a printed circuit board inside or from an antenna. Specifically, in case of making a phone call, a user is very close to the mobile communication terminal or from comes into contact with the mobile communication terminal. As a result, there is a problem that the electromagnetic waves may affect the user negatively.
SAR defines a reference for a rate of electromagnetic waves absorbed in a human body. SAR is an abbreviation for Specific Absorption Rate, i.e., a rate of electromagnetic waves absorbed in a human body. The reduction of SAR becomes a main task to be settled by the mobile communication terminal.
To address the problem of the electromagnetic waves affecting the human body, SAR can be reduced by grounding the electronic parts within a terminal.
FIG. 1 is a layout of a folder type mobile communication terminal according to a related art, in which a structure for grounding is shown.
Referring to FIG. 1, the mobile communication terminal according to the related art includes a terminal body 10 and a folder 20 rotatably assembled to one end portion of the terminal body 10.
A PCB (printed circuit board) 11, on which various electronic parts are mounted which generate electromagnetic waves, is provided within the terminal body 10. And, an LCD (liquid crystal display) 21 is provided to the folder 20 to output an image of prescribed information. Reference number ‘22’ indicates a window for viewing the LCD 21 externally.
Both of the PCB 11 and the LCD 21 emit considerable quantities of electromagnetic waves.
The related art mobile communication terminal further includes a hinge 13 provided to one side of the terminal body 10 to enable the folder 20 to rotate against the terminal body 10, and a prescribed-size conductive plate 12 contacted with one side of the hinge 13.
The PCB/LCD 11/21 is always electrically connected to the conductive plate 12 or the conductive plate 12 and the hinge 13 for ground connection at all times. Thus, the strength of electric field within the terminal is decreased to reduce SAR, which on the other hand can reduce the communication performance of the terminal.
For instance, when the terminal is closed or when an output power is not considerably high during the use of the terminal, good transceiving can be sufficiently performed in an intense electric field area providing an excellent mobile communication environment or a medium electric field area, although the output of the antenna is not considerably high. So, the influence of SAR is not significant while the user is making a phone call.
However, the ground connection of the terminal considerably reduces radio communication/reception performance of the terminal, which is not desirable.